干旱区生态环境知识资源中心

In this paper, we consider the attentional demands associated with detecting and responding to predators, or ’apprehension’, and the within-patch search of Allenby’s gerbils, Gerbillus andersoni allenbyi. We, thus, present a first empirical investigation of the indirect, informational consequences of perceived predation risk. Specifically, we focus on the ability to track the quality of seed patches in sandy habitats. There are two potential effects here; since instantaneous intake rate (or some proxy) is the key parameter of interest to an optimal forager, apprehension can interfere with the estimation of: (1) the number of food items captured, and/or (2) the time taken to capture them (the ability to locate food items). Only (2) will have a consistent effect on patch quality, and we test the hypothesis that increased predation risk reduces gerbil search efficiency. We therefore quantified gerbil search paths in patches of uniform seed distribution that differed in their associated risks of predation by manipulating the presence of barn owls, Tyto alba, and light in an aviary. Gerbil search was more random under risky conditions. We discuss the implications of this result for information processing and patch use under predation risk, and the foraging games between gerbils and owls in the Negev Desert.